content: /*
   * Copyright 2016-present David Karnok
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package hu.akarnokd.rxjava3.expr;
  
  import java.util.concurrent.atomic.AtomicInteger;
  
  import org.reactivestreams.*;
  
  import io.reactivex.rxjava3.core.Flowable;
  import io.reactivex.rxjava3.exceptions.Exceptions;
  import io.reactivex.rxjava3.functions.BooleanSupplier;
  import io.reactivex.rxjava3.internal.subscriptions.*;
  
  final class FlowableWhileDoWhile<T> extends Flowable<T> {
  
      final Publisher<? extends T> source;
  
      final BooleanSupplier preCondition;
  
      final BooleanSupplier postCondition;
  
      FlowableWhileDoWhile(Publisher<? extends T> source, BooleanSupplier preCondition,
              BooleanSupplier postCondition) {
          this.source = source;
          this.preCondition = preCondition;
          this.postCondition = postCondition;
      }
  
      @Override
      protected void subscribeActual(Subscriber<? super T> s) {
          boolean b;
  
          try {
              b = preCondition.getAsBoolean();
          } catch (Throwable ex) {
              Exceptions.throwIfFatal(ex);
              EmptySubscription.error(ex, s);
              return;
          }
  
          if (b) {
              WhileDoWhileObserver<T> parent = new WhileDoWhileObserver<>(s, postCondition, source);
              s.onSubscribe(parent);
              parent.subscribeNext();
          } else {
              EmptySubscription.complete(s);
          }
      }
  
      static final class WhileDoWhileObserver<T>
      extends SubscriptionArbiter
      implements Subscriber<T>, Subscription {
  
          private static final long serialVersionUID = -5255585317630843019L;
  
          final Subscriber<? super T> downstream;
  
          final AtomicInteger wip;
  
          final BooleanSupplier postCondition;
  
          final Publisher<? extends T> source;
  
          volatile boolean active;
  
          long produced;
  
          WhileDoWhileObserver(Subscriber<? super T> downstream, BooleanSupplier postCondition, Publisher<? extends T> source) {
              super(false);
              this.downstream = downstream;
              this.wip = new AtomicInteger();
              this.postCondition = postCondition;
              this.source = source;
          }
  
          @Override
          public void onSubscribe(Subscription s) {
              super.setSubscription(s);
          }
  
          @Override
          public void onNext(T value) {
              produced++;
              downstream.onNext(value);
          }
  
          @Override
          public void onError(Throwable e) {
              downstream.onError(e);
          }
  
          @Override
          public void onComplete() {
  
              boolean b;
  
              try {
                  b = postCondition.getAsBoolean();
              } catch (Throwable ex) {
                  Exceptions.throwIfFatal(ex);
                  downstream.onError(ex);
                  return;
              }
  
              if (b) {
                  long p = produced;
                  if (p != 0L) {
                      produced(p);
                  }
  
                  active = false;
                  subscribeNext();
              } else {
                  downstream.onComplete();
              }
          }
  
          void subscribeNext() {
              if (wip.getAndIncrement() != 0) {
                  return;
              }
  
              for (;;) {
  
                  if (isCancelled()) {
                      return;
                  }
  
                  if (!active) {
                      active = true;
                      source.subscribe(this);
                  }
  
                  if (wip.decrementAndGet() == 0) {
                      break;
                  }
              }
          }
      }
  }
  